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Groups > comp.lang.python > #39266

Re: improving performance of writing into a pipe

Date 2013-02-19 10:47 -0700
From Michael Torrie <torriem@gmail.com>
Subject Re: improving performance of writing into a pipe
References (2 earlier) <16e85bd1-6e5d-4d70-95bf-cc6b986a9f7c@googlegroups.com> <kftm2l$b84$1@r03.glglgl.gl> <8f26ac4d-4732-46ac-bf4e-877696b22241@googlegroups.com> <mailman.1958.1361211131.2939.python-list@python.org> <85cd2254-0800-4448-9117-9175bbfd10f6@googlegroups.com>
Newsgroups comp.lang.python
Message-ID <mailman.2055.1361296049.2939.python-list@python.org> (permalink)

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On 02/19/2013 02:24 AM, mikprog@gmail.com wrote:
> Or rather: what would you try to catch in this particular case?

As Peter said, nothing for now.  But you seem very resistant to telling
us what exception was raised.

Though looking at your code more closely I can see that likely the error
is related to the fact that /tmp/mypipe is not an executable program.
popen (which is deprecated and replaced by the subprocess module) is for
running programs and communicating with them over pipes created by the
popen function.  So your code is not likely to ever work as it is
presently given.

Here's the bash equivalent of your code:

$ mkfifo /tmp/path
$ cat </tmp/path &
$ echo hello, world | /tmp/path

Bash will say, "bash: /tmp/path: Permission denied"

The correct bash line is:
$ echo hello, world > /tmp/path

popen() (and subprocess) is the equivalent of the first bash command.
open() is the equivalent of the second line.

Do you understand the difference?

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improving performance of writing into a pipe mikprog@gmail.com - 2013-02-18 07:12 -0800
  Re: improving performance of writing into a pipe Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-02-18 15:21 +0000
    Re: improving performance of writing into a pipe mikprog@gmail.com - 2013-02-18 08:31 -0800
      Re: improving performance of writing into a pipe Thomas Rachel <nutznetz-0c1b6768-bfa9-48d5-a470-7603bd3aa915@spamschutz.glglgl.de> - 2013-02-18 17:49 +0100
        Re: improving performance of writing into a pipe mikprog@gmail.com - 2013-02-18 09:00 -0800
          Re: improving performance of writing into a pipe Michael Torrie <torriem@gmail.com> - 2013-02-18 11:12 -0700
            Re: improving performance of writing into a pipe mikprog@gmail.com - 2013-02-19 01:24 -0800
              Re: improving performance of writing into a pipe Peter Otten <__peter__@web.de> - 2013-02-19 10:55 +0100
                Re: improving performance of writing into a pipe mikprog@gmail.com - 2013-02-19 02:27 -0800
                Re: improving performance of writing into a pipe Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-02-19 11:15 +0000
                Re: improving performance of writing into a pipe mikprog@gmail.com - 2013-02-19 02:27 -0800
              Re: improving performance of writing into a pipe Michael Torrie <torriem@gmail.com> - 2013-02-19 10:47 -0700
                Re: improving performance of writing into a pipe mikprog@gmail.com - 2013-02-20 09:54 -0800
                Re: improving performance of writing into a pipe John Gordon <gordon@panix.com> - 2013-02-20 18:39 +0000
                Re: improving performance of writing into a pipe Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-02-20 22:05 +0000
                Re: improving performance of writing into a pipe mikprog@gmail.com - 2013-02-20 09:54 -0800
            Re: improving performance of writing into a pipe mikprog@gmail.com - 2013-02-19 01:24 -0800
    Re: improving performance of writing into a pipe mikprog@gmail.com - 2013-02-18 08:31 -0800
  Re: improving performance of writing into a pipe Serhiy Storchaka <storchaka@gmail.com> - 2013-02-18 21:29 +0200
    Re: improving performance of writing into a pipe mikprog@gmail.com - 2013-02-19 04:10 -0800
    Re: improving performance of writing into a pipe mikprog@gmail.com - 2013-02-19 04:10 -0800
    Re: improving performance of writing into a pipe mikprog@gmail.com - 2013-02-19 05:39 -0800
      Re: improving performance of writing into a pipe Peter Otten <__peter__@web.de> - 2013-02-19 14:57 +0100
        Re: improving performance of writing into a pipe mikprog@gmail.com - 2013-02-19 06:38 -0800
        Re: improving performance of writing into a pipe mikprog@gmail.com - 2013-02-19 06:38 -0800
    Re: improving performance of writing into a pipe mikprog@gmail.com - 2013-02-19 05:39 -0800

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